West Coast Of Korea Research Articles

Genetic differentiation in seven geographic populations of the fleshy shrimp Penaeus ( Fenneropenaeus) chinensis based on microsatellite DNA

Microsatellite DNA markers were used to investigate the genetic diversity of Penaeus ( Fenneropenaeus) chinensis, a topic of controversy in previous studies. A total of 210 individual shrimps were collected in seven geographic locations in the Yellow and Bohai Seas: Liaodong Bay (LD), Bohai Bay (BH), Haizhou Bay (HZ), Rushan Bay (RS), Haiyangdao fishing ground (HYD), the west coast (KW), and the south coast of the Korean Peninsula (KS). A new population of P. chinensis was identified in KS. A total of 109 alleles were identified from seven loci. Among the 49 population loci, 34 showed significant deviation from the Hardy–Weinberg equilibrium. Cluster analysis using UPGMA revealed a close genetic relationship of P. chinensis between BH and LD and between RS and HZ, while the shrimp from KW and KS diverged. Genetic distance and AMOVA analysis identified three areas with distinct populations: the Bohai and Yellow Seas along the Chinese coast; the west coast of Korea, and the south coast of Korea. These results are consistent with tagging–recapture data and some molecular DNA marker studies, but different from results by mitochondrial gene methods.

Sediment transport processes over a sand bank in macrotidal Garolim Bay, west coast of Korea

A sand bank at the mouth of macrotidal Garolim Bay, west coast of Korea is investigated by means of morphological surveys and current measurements for unraveling sediment transport processes relevant to its formation and maintenance. Bedload transport rates calculated from current data show that mutually evasive tidal currents flowing obliquely to the bank through surrounding channels play a principal role on sediment transport over the sand bank. Flood-oriented bedload transport is dominant on the eastern flank of the bank, whereas ebb-oriented transport dominates the western flank, resulting in bedload convergence towards the crest. Surface bedforms, mostly large dunes, suggest a clockwise sand transport around the sand bank, generally coincident with the pattern revealed by bedload calculations. Although the tidal currents are principal processes responsible for the sand-bank dynamics, the predominance of flood-oriented dunes at the bay mouth is indicative of a significant role of winter waves enhancing flood-oriented transport at the mouth. The sand bank appears to be in a dynamic equilibrium, since it has remained stationary for last 25 years.

Airborne mercury pollution from a large oil spill accident on the west coast of Korea

Atmospheric mercury pollution was recognized after a large oil spill on the west coast of Korea on 7 December 2007. In this study, the concentrations of gaseous elemental mercury (GEM: Hg 0) in air were measured both shortly after the oil spill (∼100 h) and 1 month after the accident near the accident site. When the Hg concentration levels were compared between two seashore sites and two parallel sites offshore, the values tend to decrease further offshore. The unusual rise in Hg concentration levels observed on the seashore area shortly after the accident (mean of 16.4 ± 9.85 ng m −3) dropped dramatically after 1 month with active cleanup activities (2.99 ± 1.40 ng m −3). Because of the connection between crude oil and Hg (one of the major impurities), the unusual rise in the atmospheric Hg after the oil spill can be explained by the active evasion of Hg from the spilled crude oil. Although Hg levels determined a few days after the accident did not exceed the reference exposure limits (REL) proposed by several agencies, the early build-up of elemental mercury level due to the oil spill might have exerted certain impacts on the surrounding environments.

태안 유출 원유의 생물정화를 위한 유용미생물 적용

We have studied bioremediation of effective microorganisms on crude oil spill in Taean, west-coast of Korea. Oil contaminated soil samples were collected on December 14, 2007, seven days after the Hebei Spirit oil-spilled accident. Total petroleum hydrocarbon (TPH) was measured to evaluate the effectiveness of effective microorganisms (EM) which were composed with yeast, photosynthetic bacteria and lactic acid bacteria on oil degradation. TPH concentration before EM treatment was 323.8 mg/kg, whereas TPH concentrations on 2 days after EM treatment and that of control (without EM) was 102.1 mg/kg and 170.6 mg/kg, respectively. On six days after EM treatment TPH was 91.3 mg/kg and that of control was 127.7 mg/kg. Percentages of degraded crude oil were 47.3% without EM and 68.5% with EM, 60.6% without EM and 71.8% with EM on 2 and 6 days after EM treatment, respectively. These results clearly showed that the application of effective microorganisms toward oil-contaminated soil was quite useful to degrade crude oil spill. These results were derived from the effects of biostimulation of microbial media nutrients and bioaugmentation of effective microorganisms. If we carefully apply these effective microorganisms, it can be a useful bioremediation method to recover oil-contaminated marine ecosystems.

Changes in topography and surface sediments by the Saemangeum dyke in an estuarine complex, west coast of Korea

The effects of a giant offshore dyke, Saemangeum, have been of special interest on both scientific and environmental aspects. Without any rival worldwide with regard to the ample scale and estuarine setting, the Saemangeum dyke and its vicinity (Saemangeum Area) should be an unprecedented experimental site for monitoring the consequence of the estuarine developments with dykes. In order to unravel geologic changes caused by the Saemangeum dyke, we collected a number of surface sediment samples and bathymetric profiles from a full coverage of the Saemangeum Area, and compared topography and sediment phase on the inter-annual (2002–2006, post-construction) and decadal (1982–2002, between pre- and post-construction) timescales. The dyke construction induced vigorous erosion along the dyke, especially across a few open gaps between dyke segments. These open gaps led to forming deep erosional troughs and the associated channels to the river mouth. At the same time, mild accumulation of sediments occurred on the broad seafloor offshore the erosional zone of dyke sector IV and on shoals between the erosional troughs off dyke sectors I–II. Inside the dyke, tidal flats have become expanded and aggraded with continuously discharged riverine sediments. Sands have been newly introduced into the offshore area of sector IV owing to tidal currents with an orientation forced to be parallel to sector IV (NE–SW), reinforced by high waves during winter. By contrast, the expanded sandy area off sectors I–II resulted from redistribution of pre-existing sands without any new input from offshore. As a whole, the concentrated erosion and sandy-seafloor expansion offshore represent the man-made influences triggered by the Saemangeum dyke.

Coastal Dune Luminescence Chronologies Indicating a Mid-Holocene Highstand along the East Coast of the Yellow Sea

Abstract Previous studies of Holocene sea-level change along the Yellow Sea coastline present conflicting reconstructions, and such investigations have invariably used peat as well as other biological markers as paleo-indicators of relative sea level. An alternative proxy indicator of sea-level change is employed in this study by applying the luminescence dating technique on quartz sands retrieved from relict foredune structures on a tectonically stable section of the west coast of Korea. The chronologies obtained are consistent with a relative sea level that was very close to or higher than present during the period ca. 6–5 ka. Such ages do not accord with a sea level that rose continuously throughout the Holocene, as is suggested by some earlier studies. The mid-Holocene highstand identified in this study indicates that sea-level change along the Yellow Sea shoreline is congruous with sea-level curves reported from other far-field sites at which crustal hydroisostatic adjustment presumably led to the tr...

Impact of high concentrations of manganese on the survival of short neck clam Ruditapes philippinarum juveniles in sandy tidal flat sediment in Ariake Bay, Kyushu, Japan

Ruditapes philippinarum is a popular edible clam that occurs densely on the sandy tidal flats on the Japanese coast. However, on the tidal flats in Ariake Bay in Kumamoto Prefecture, western Japan, the clam suffered from extremely high mortality just after settlement on the sediment and this mortality seriously affected the population persistence of the clam. In this study, we focused on the negative impact of manganese in the sediment on the juvenile clam. We surveyed manganese ion concentration in the interstitial water of the sediment on three different sandy tidal flats facing Ariake Bay in Kumamoto Prefecture and one in the west coast of Korea. We conducted laboratory experiments exposing juvenile clam just after settlement to different contents of manganese dioxide in the sediment or manganese ion in the water: with sand containing high content of manganese dioxide (2,300 mg kg−1 dry sediment; henceforth Experiment 1); with seawater containing 5.4 mg L−1 of manganese ion (Experiment 2); and with natural sand and seawater containing 5.4 mg L−1 of manganese ion (Experiment 3). Significant mortality was not noted in Experiment 1 or in Experiment 2, while high mortality was seen in Experiment 3. In the field survey, we detected manganese ion concentration in the interstitial water at only 2.78 mg L−1 on the Arao Tidal Flat. However, we confirmed that manganese ion concentration in the interstitial water became more than 40 mg L−1 in the extraction test with the sediment on the Arao Tidal Flat. These results indicate that manganese ion liquated from the sediment into the interstitial water, due to reduction of manganese oxide, may influence seriously the physiology of juvenile clams on the tidal flats.

Line Transect에서 발견율함수 추정에 사용되는 모델에 따른 상괭이, Neophocaena phocaenoides의 자원개체수 추정

Line transect sampling in a sighting survey is one of most widely used methods for assessing animal abundance. This study applied distance data, collected from three sighting surveys using line transects for finless porpoise that were conducted in 2004 and 2005 off the west coast of Korea, to four models (hazard-rate, uniform, half-normal and exponential) that can use a variety of detection functions, g (x). The hazard-rate model, a derived model for the detection function, should have a shoulder condition chosen using the AIC (Akaike Information Criterion), as the most suitable model. However, it did not describe a shoulder shape for the value of g(x) near the track tine and underestimated g (x), just as the exponential model did. The hazard-rate model showed a bias toward overestimating the densities of finless porpoises with a higher coefficient of variation (CV) than the other models did. The uniform model underestimated the densities of finless porpoise but had the lowest CV. The half-normal model described a detection function with a shape similar to that of the uniform model. The half-normal model was robust for finless porpoise data and should be able to avoid density underestimation. The estimated abundance of finless porpoise was 3,602 individuals (95% CI=1,251-10,371) inshore in 2005 and 33,045 individuals (95% CI=24,274-44,985) offshore in 2004.

Morphological Change at Byunsan Beach, West Coast of Korea; 14-years Monitoring During the Saemangum Reclamation Project

Morphological Change at Byunsan Beach, West Coast of Korea; 14-years Monitoring During the Saemangum Reclamation Project

한국 서해 경기만 연안역에서 수질환경의 시.공간적 변화 특성과 조절 요인

Temporal (seasonal) and spatial distributions and variations of various physico-chemical factors (salinity, temperature, pH, DO, COD, SPM, POC, silicate, DIP, DIN) in surface and bottom waters were studied in the coastal environment with typical macro-tidal range and monsoonal weather condition, Gyeonggi Bay, west coast of Korea. Spacial distribution patterns of these factors were generally similar to each other, and appeared to be inversely related to the distribution pattern of salinity, suggesting that water quality of the study area was primarily controlled by the physical mixing process of Han-River freshwater with nearby coastal seawater. During flooding season, silicate- and nitrogen-rich Han River water directly flowed into offshore as far as <TEX>$20\sim30\;km$</TEX> from the river mouth, probably causing serious environmental problems such as eutrophication and unusual and/or noxious algal bloom, etc. Except the surface water during summer flooding season, high concentrations of nutrients appeared generally in dry season, whereas low values in spring, possibly because of the occurrence of spring phytoplankton bloom. On the other hand, nutrient flux through the estuary seems to be primarily depending on river discharge, sewage discharge and agricultural activities, especially during the rainy season. Also, nutrients in this coastal waters are considered to be supplied from the sediments of tidal-flats, which developed extensively around the Han-River mouth, especially during fall and winter of dry and low discharge seasons, possibly due to the stirring of tidal flat sediments with highly enriched pore-water nutrients by storm. And also, COD and DIN concentrations in the study area consistently increased during the last 20 years, probably because of agricultural activities and increasing discharge of industrial and domestic wastes.

곰소만 조간대 퇴적물의 장기적 변화

곰소만 조간대 퇴적물의 장기적 변화를 조사하기 위하여 1991년과 2006년에 채취된 표층퇴적물 시료를 분석하고, 그 결과를 비교하였다. 만 입구 조간대에서는 실트와 점토의 함량이 감소하고 모래의 함량이 증가하였다. 만의 중부와 상부 조간대에서는 모래와 점토의 함량이 감소하고 실트의 함량이 증가하였다. 특히 점토의 함량은 주변의 다른 반폐쇄된 조간대에 비해 상대적으로 매우 낮은 함량 분포를 보였으며, 1991년에 비해서도 뚜렷하게 감소하는 경향을 보였다. 퇴적물 구성성분의 뚜렷한 함량 변화는 퇴적상의 변화를 초래하였다. 이러한 변화는 매립 및 호안건설에 의한 해안선의 변형과 간조선 부근에 빽빽하게 설치된 양식장의 구조물, 그리고 곰소만 북쪽의 새만금 방조제 건설 등에 의한 수리에너지 조건의 변화에 기인한 것으로 해석된다. In Gomso Bay, on the west coast of Korea, the surface sediments sampled in 1991 and 2006 were analysed to identify the long-term variations of tidal flat sediments. Silt and clay contents have decreased in the bay-mouth tidal flats whereas sand and clay contents have decreased on the inner-bay and bay-head tidal flats over the last 15 year period. In particular, the clay contents of the tidal flats in 2006 were relatively low when compared to those of both tidal flats adjacent to other semi-enclosed bays and those of the tidal flats in 1991. The variations of textural compositions in the tidal flat sediments have led to changes of the sedimentary facies. It indicates that the changes must have been made by the changes of hydrodynamic conditions impacted by human activities, such as the construction of sea-walls, land reclamation, structures of farms constructed compactly near the low water line, and the Saemangeum dyke constructed in the northern part of the area where this research was conducted.

통발 어구를 이용한 서해 경기만 사각형어초 시설의 효과 평가

통발 어구를 이용한 서해 경기만 사각형어초 시설의 효과 평가

Sources and transformations of N in reclaimed coastal tidelands: evidence from soil δ15N data

Electrical conductivity of saturated soil ex- tracts (ECe) in three reclaimed tideland (RTL) soils on the west coast of Korea decreased with time since reclama- tion, indicating natural desalinization through leaching of salts by precipitation water. Soil N concentration in- creased with decreasing ECe. With the increase in soil N concentration, the d 15 N decreased, likely caused by the input of 15 N-depleted N sources. As N2-fixing plant spe- cies were found in the oldest RTL, atmospheric N2 fixa- tion likely contributed to the increase in soil N concentration in the oldest RTL. Negative d 15 N (-7.1 to -2.0&) of total inorganic N (NH4 + +NO3 - ) and published data on N deposition near the study area indicate that atmospheric N deposition might be another source of N in the RTLs. Meanwhile, the consistently negative d 15 No f soil NO3 - excluded N input from chemical fertilizer through groundwater flow as a potential N source, since NO3 - in groundwater generally have a positive d 15 N. The patterns of d 15 No f NH 4 + (+2.3 to +5.1&) and NO3 - (-9.2 to -5.0&) suggested that nitrification was an active pro- cess that caused 15 N enrichment in NH4 + but denitrifica- tion was probably minimal which would otherwise have caused 15 N enrichment in NO3 - . A quantitative approach on N budget would provide a better understanding of soil N dynamics in the studied RTLs.

An Analysis of the Decision Factors on Mokpo Port by Multinomial Logit Model

Relative importance of maritime transport that takes charge of main current of freight in country' economy is very large. Especially, port and facility carry out important role which treats freight of import and export smoothly and improves international trade as turning point, to achieve key role on connection and association between sea and land. For such reason, enlargement of port facilities or development of port needs to grasp exactly the utilization of port, attributes and selective factors of shipper. On the other hand, the amounts of physical distribution on Mokpo port located in Korean west coast are increasing, with fast economic growth of East Asian including China. This study uses discrete choice model that is measuring to analyze attribute and characteristic of Mokpo port, and analyzes port selection by decision factors of shipper. This paper composed a questionnaire using the result of preceding research, to decide port selection factor among competitive ports. Through factor analysis on a basis of the questionnaire' result, five principal components were extracted. These are resorted out by Logit model, to grasp competitive elements of port. This research fin present direction which raises competitive power of ports in west coast of Korea, especially on alternative and concentration of middle-class port as Mokpo may be useful.

갯벌 지역의 하부퇴적층에 대한 AMT 탐사의 적용 가능성 평가

The marine seismic prospecting using a research vessel in the shallow sea near the coastal area has certain limits according to the water depth and survey environment. Also, for the electrical resistivity survey at seashore area, one may need a specially designed high-voltage source to penetrate the very conductive surface layer. Therefore, we have conducted a feasibility study on the application of magnetotelluric method (MT), a passive geophysical method, on investigating of shallow marine environment geology. Our study involves both theoretical modeling and field survey at the tidal flat area which represent the very shallow marine environment. We have applied the audio-frequency magnetotelluric (AMT) method to the intertidal deposits of Gunhung Bay, west coast of Korea, and analysed the field data both qualitatively and quantitatively to investigate the morphology and sedimentary stratigraphy of the tidal flat. The inversion of AMT data well reveals the upper sedimentary layer of Holocene intertidal sediments having a range of 13-20 m thickness and the erosional patterns at the unconformable contact boundary. However, the AMT inversion results tend to overestimate the depth of basement (30-50 m) when compared with the seismic section (27-33 m). Since MT responses are not significantly sensitive to the resistivity of middle layer or the depth of basement, the AMT inversion result for basement may have to be adjusted using the comparison with other geophysical information like seismic section or logging data if possible. But, the AMT method can be an effective alternative choice for investigating the seashore area to get important basic informations such as the depositional environment of the tidal flat, sea-water intrusion and the basement structure near the sea shore.

Screening and characterization of a novel fibrinolytic metalloprotease from a metagenomic library

A metagenomic library was constructed using total genomic DNA extracted from the mud in the west coast of Korea and was used together with a fosmid vector, pCC1FOS in order to uncover novel gene sources. One clone from approximately 30,000 recombinant Escherichia coli clones was identified that showed proteolytic activity. The gene for the proteolytic enzyme was subcloned into pUC19 and sequenced, and a database search for homologies revealed it to be a zinc-dependent metalloprotease. The cloned gene included the intact coding gene for a novel metalloproteinase and its own promoter. It comprised an open reading frame of 1,080 base pairs, which encodes a protein of 39,490 Da consisting of 359 amino acid residues. A His-Glu-X-X-His sequence, which is a conserved sequence in the active site of zinc-dependent metalloproteases, was found in the deduced amino acid sequence of the gene, suggesting that the enzyme is a zinc-dependent metalloprotease. The purified enzyme showed optimal activity at 50 degrees C for 1 h and pH 7.0. The enzyme activity was inhibited by metal-chelating reagents, such as EDTA, EGTA and 1,10-phenanthroline. The enzyme hydrolyzed azocasein as well as fibrin. Thus, the enzyme could be useful as a therapeutic agent to treat thrombosis.

새만금 갯벌의 퇴적환경 변화

The Saemangeum tidal flat with an area of approximately 233 ㎢ is one of the biggest estuarine tidal flats on the west coast of Korea. Because of its location in the estuary of Mangyeong and Dongjin Rivers, the tidal flat receives large amount of sediments. A 33-㎞ long sea dyke, enclosing a coastal zone of 401 ㎢, was constructed to reclaim tidal flat in the Saemangeum area. The dyke construction radically changes the local tidal current regime and estuarine circulation. These have an effect on sedimentary environments in the tidal flat. On the tidal flats of the study area net deposition occurred, but net erosion occurred near tidal channel in 2004. The comparison of topography and surface sediments in summer 2004 with those in summer 1988 before the dyke construction showed that elevation increased with maximum 80cm and mean grain sizes were fining at Gwanghwal tidal flats. Sedimentary facies of two cores from Gwanghwal tidal flat revealed homogeneous layers in the upper part, suggesting rapid deposition after the dyke construction. The sedimentation rate in Gwanghwal tidal flat(GW 6) using ²¹?Pb analysis was about 5.4 ㎝/yr, which is well matched with the sedimentation pattern revealed by change in topography.

Late Quaternary evolution of macrotidal Kimpo tidal flat, Kyonggi Bay, west coast of Korea

Up to 32 m thick late Quaternary deposits are developed in the Kimpo tidal flat, Kyonggi Bay, west coast of Korea. The deposits consist of six lithofacies units that are grouped into three unconformity-bounded sequences, which formed in response to late Quaternary sea-level fluctuations. The lowermost sequence (S3) consists of late Pleistocene fluvial deposits (Unit VI) and overlying tidal deposits (Unit V). Unit VI is interpreted to have formed in a meandering channel and associated floodplain environment. Weak pedoturbation characterizing the upper part of Unit VI suggests that pedogenesis occurred prior to initial transgression. Well-developed tidal rhythmicities in Unit V indicate that tidal sedimentation prevailed during the first marine inundation. Intermediate sequence (S2) is composed of late Pleistocene fluvial deposits (Unit IV) and overlying tidal deposits (Unit III). Depositional environments of Unit IV and Unit III are similar to those of Unit VI and Unit V, respectively. Upper parts of Unit IV and Unit III are variably indurated and pedoturbated, suggesting prolonged subaerial exposure. The uppermost sequence (S1) consists of early Holocene sphaerosiderite-rich marsh deposits (Unit II) and overlying middle to late Holocene tidal deposits (Unit I). Pervasive occurrence of similar tidal rhythmites in both Holocene and late Pleistocene tidal deposits indicates that tidal environment recurred over several sea-level cycles. Age dates and stratigraphic position indicate that Holocene tidal deposits were formed since 7–8 ka BP. Given the validity of age dates, however, timing of late Pleistocene tidal deposits is controversial in the light of eustatic sea-level curves. Considering tectonically stable condition of study area, the elevation of the late Pleistocene tidal deposits is too high to fit the curves. Elucidation of the exact timing of the tidal deposits requires more independent age controls as well as further understanding on the tectonic regime of the west coast of Korea.

강화 동검도 염습지 식생의 분포와 저서환경조건의 시.공간적 변화

We examined the effect of salt marsh vegetation on the benthic environment in macro-tidal flats at Donggeomdo, Ganghwa, on the west coast of Korea. Nine stations were established along a transect across the tidal flats, including salt marsh, and field sampling was conducted monthly from July 1997 to June 1998. During the study period, environmental parameters fluctuated as follows: salinity, 15.0 to 28.2 psu, exposure time, 613 to 702 hr/m, inundation time, 28 to 117 hr/m, sediment organic carbon, 0.71 to 1.34%, nitrogen, 0.07 to 0.16%, sulfur from 0.07 to 0.22%, mean grain size from 6.3 to , water content from 19.4 to 44.4%, water temperature from 4.4 to and temperature of the surface sediments, 2.7 to , in total, seven halophyte species were sampled and found to be vertically distributed across the tidal levels. Carer scabrifolia, Suaeda maritima, Limonium tetragonum and Phragmites communis dominated the upper zone of the salt marsh, Juncus haenkei, Triglochin maritimum and P. communis dominated the middle zone, and Suaeda japonica predominated in the lower area. Principal component analysis (PCA) and non-metric multi-dimensional scaling revealed that the zonation of halophytes was related to environmental variables such as salinity and exposure time. The halophyte communities were likely related to the organic content of the surface sediment.

Report on the occurrence of brown ring disease (BRD) in Manila clam, Ruditapes philippinarum, on the west coast of Korea

This is the first report on the occurrence of Vibrio tapetis, the brown ring disease (BRD) agent in Manila clam, Ruditapes philippinarum, in Asian waters. Brown conchiolin deposits, a distinct sign of BRD, were observed on the inner shells of clams collected from Anmyeondo Island, on the west coast of Korea. The infection intensity, based on the appearance of conchiolin deposits, ranged from 1–2, indicating that BRD of clams is in the initial phase. There was a negative correlation between the level of BRD and the condition index of the clams ( P < 0.05). Extrapallial fluid from infected clams was collected and incubated in marine broth at 18 °C for 20 h to obtain genomic DNA of the BRD agent. Vibrio tapetis-specific 16S rRNA was amplified by polymerase chain reaction using a V. tapetis-specific primer pair. The DNA sequences of the BRD agent isolated in this study showed 99.0–99.3% similarity to V. tapetis reported from France and Norway, suggesting that the causative agent of BRD observed in this study was V. tapetis or taxonomically close to V. tapetis reported in Europe.